(i) Field of the Invention
The present invention relates to a clothes dryer and, more specifically, it relates to a dehumidifying type or condensation type clothes dryer which has a dual side bladed fan of heat exchange type for circulating heated air in a drying chamber while taking in or out the external air as cooling air. The fan serves as a heat exchanger between the heated air and the cooling air to remove moisture from the heated air. Then, the heated air is re-heated by a heater and is supplied to the drying chamber.
(ii) Description of the Prior Art
An example of a clothes dryer of the above stated type is disclosed in Japanese Pat. Publication No. 56518/1985. The dryer is provided with an air duct at an outlet of a tumbling drum, or a drying chamber. The air duct has an opening at its rear portion, and a heat exchange type dual side bladed fan is provided with in the opening to partition off the air duct. A seal member is interposed between the periphery of the dual side bladed fan and a lip of the duct opening to air-tightly separate a duct into a front path for heated air and a rear path for cooling air. When the dual side bladed fan is rotated in drying operation, heated air is circulated in the drying chamber with the front surface of the dual side bladed fan while cooling air, or the external air being taken in or out to come in contact with the rear surface of the dual side bladed fan. Thus, heated air and cooling air are subjected to a heat exchange, and water obtained from the heated air is collected in the heated air path.
Meanwhile, although the sealing member is inserted, the paths for heated air and for cooling air may communicate with each other because of the vibration of the rotating fan or its small displacement in the direction of thrust. When heated air leaks into the cooling air path and moisture in the heated air condenses into water, for example, the water cannot be collected together with the water in the heated air path. On the other hand, the heated air leaks out of the dryer without condensation, the environmental air around the dryer comes to have high humidity.
A dryer disclosed in Japanese Pat. Laid-Open No. 32998/1983 and Japanese Pat. Laid-Open No. 57099/1983 is provided with a clearance between the periphery of a heat exchange type dual side bladed fan and an opposite partition to form a bent path so that high seal effect can be obtained. Also, a dryer disclosed in Japanese Patent Laid-Open No. 284300/1986 is provided with a labyrinth seal PG,4 between a fan and a partition so that the rotational force of the fan is not reduced due to the friction force in sealing.
However, with regard to the prior art seal, heated air unavoidably leaks from one side of the dual side bladed fan to the other, that is, from a path for heated air to a path for cooling air. As a result, the rate of water obtained through condensation of moisture in heated air, or the dehumidifying (condensation) rate is lower than 50%.
Accordingly, it is an object of the present invention to provide a clothes dryer which employs the labyrinth seal having a relatively good seal effect to inhibit leakage of heated air and improve the dehumidifying rate.
It may be considered that a top panel of a dryer or electrical devices within the dryer machine is cooled off using cooling air flowing the above mentioned cooling air path. However, when an opening is made in a part of the wall of the cooling air path to divide a stream of cooling air, the pressure within the cooling air path comes to be lower than that within the heated air path. This may cause water produced through condensation at a seal portion or water running down thereon to be pushed out into the cooling air path.
Accordingly, it is another object of the present invention to provide a clothes dryer which employs a labyrinth seal having a relatively good seal effect to ensure a cooling effect so that water removed from heated air can be assuredly held with in the heated air path.